Raman Spectrometer

Raman Spectrometer

Chemistry, Spectroscopy

Functional: The Raman Spectrometer was and is used to measure stretching of bonds by measuring the inelastic scattering of light, which are output in lines of light also known as excitation lines, for the sample being collected. To test a sample the experimenter would place a glass capillary tube with a sample of the material being detected on the sampling apparatus, which is a black pedestal surrounded by concave mirrors, or under the microscope. The mirrors found around the apparatus will reflect light back at the sample from different angles so as to get the best reading of raman by testing the sample from all angles. Another way to test the sample would be to place the sample under the microscope, which is found to the left of the black pedestal when viewed from the front, on a glass plate. The microscope then scans the energy lines using its own scanning mirrors to measure the sample from all sides. The microscope is best utilized when something is under high temperatures and pressures (Hariba). Next the laser must be set to the right intensity and frequency, which can be determined by the ampere meter and the power meter, depending on the sample. “Samples are excited using either an argon ion laser or krypton ion laser which provide a multitude of excitation lines”(University of Sydney). This allows for accurate measurement of the vibrations of the sample. The laser is initiated by the user and once turned on will shine through a series of mirrors ,located around the base of the machine, and lenses, which are maneuverable and set by the operator to concentrate the light to one intensity before it hits the sample, which can also be moved up and down using the black knob attached to the apparatus. The concave mirrors will reflect the laser back towards the sample and then the shift in wavelength is then observed for the sample by a detector, in this case a photomultiplier, that measures the intensity of light leaving the sample. The photomultiplier provides analysis of the sample around the range of 1.5 um. The machine will also output a numerical value for the change in Raman on the top of the machine. The experimenter then reads this information given a graphical representation of the shift in wavelength.

Physical: The Raman Spectrometer consists of a large rectangular center module made of sheet metal. Surrounding this main piece are various instruments and dials. The whole system is set up on a table; on the back side of the center structure there is a laser emitter which is the longest object on the table, extending the entire length (1820 mm). The laser is sent through a series of lenses and mirrors that wrap around to the front of the system and shine into the sampling apparatus. The sampling apparatus is a stage in a square box with concave mirrors located on three out of the four faces with the other face allowing the laser light in. To the right of the sampling apparatus is a microscope that is used similarly to the sample apparatus. On top of the main housing, from left to right, there is a power meter in the front, in the middle back there is a meter measuring cm and change in centimeters, and on the far right there is a small digital display. The on/off switch is located on the right face of the machine behind the microscope.

Emily Lilla, Patrick Kidwell, Jacob Walcott, Kennedy Oparka, and Kelsey Bland

1928: Invented

C.V Raman & K.S. Krishnan

Similar to IR Spectrophotometers

Physical Object

English

U 1000

1.82 m length x 1.07 m width x 0.6 m height

Steel, Glass, and Plastic

Jobin Yvon

Inscriptions:
Watt meter from 0 to 10, “WATTS” dial from “OFF” to -3 | “210 POWER METER“ “ZERO” dial | COHERENT RADIATION
Main:
”Property of Michigan Technological University | 73645”
“JOBIN | YVON | DIVISION d’INSTRUMENTS S.A. | U 1000”
“Photomultiplier Tube House | PRODUCTS FOR RESEARCH, INC. | MADE IN U.S.A”
“PHOTOMULTIPLIER | TUBE SOCKET | PRODUCTS FOR RESEARCH, INC | DANVERS MASS”
Top:
“MACRO | SPECTRA | IMAGE” “SPECTRE | IMAGE | MONOCANAL”
“Reset", Δcm-1 Raman, cm

Development of the Raman Spectrophotometer started with the conceptualization of light as both a wave and particle. Experimental results that arose from this theory were then collected and analyzed in conjecture with the demonstration that electromagnetic radiation can be scattered. The Raman Effect is the inelastic scattering of light that causes a change within the principle wavelength and thus the emitted color. While the theory was predicted some time before, experimental evidence did not exist until 1928 when C.V. Raman and K.S. Krishnan constructed the machine (Lenain 2009). One of the first experiments conducted with Raman Spectrophotometers was the passing of sunlight through a green filter and subsequently a solution of chloroform, which produced a yellow emission (Lenain 2009). Since the sample was only exposed to light, Raman analysis had the benefit of preserving samples for future use. Initially, the light source used by Raman machines was a mercury arc, but was later switched to a gas discharge lamp (Raman 2017). While a Raman spectrophotometer provides details about the polarizing nature of a molecule, it was undermined by the invention of IR spectrophotometry. Only after the invention of lasers in 1960 did research with the Raman spectrophotometer reemerge as an important tool for structural analysis (Nanophoton 2005). Later improvements of the Raman spectrophotometer included the production of better filters, lasers, and detectors (Lenain 2009).

Chemical Sciences and Engineering Building, Room 712

Arter, E. (2010, April 21). The University of Sydney - Vibrational Spectroscopy Facility. Retrieved March 19, 2017, from http://sydney.edu.au/science/chemistry/spectroscopy/instrumentation/jobin_yvon_u1000_raman.shtml

Horiba Jobin Yvon-Raman Division. T64000 and U1000. Retrieved March 22, 2017, from
http://www.horiba.com/fileadmin/uploads/Scientific/Documents/Raman/HSC-T64000_U1000-2013-V1.pdf

Lenain, Bruno. “Micro-Reactors and Micro-Analtical.” 2009, PowerPoint file,<http://depts.washington.edu/cpac/Activities/Meetings/Satellite/2009/Tuesday/Lenain%20cpac09.pdf>.

Nanophoton. "History of Raman Spectroscopy | Nanophoton." History of Raman Spectroscopy | Nanophoton. N.p., 2005. Web. 03 Mar. 2017, <https://www.sas.upenn.edu/~crulli/HistoricalPerspective.html>.